A radio receiver uses the same tuner for receiving a selected digital television (DTV) signal, irrespective of whether it is a quadrature-amplitude-modulation (QAM) or a vestigial sideband (VSB) signal. The tuner supplies a final IF signal in a 6-MHz-wide frequency band, the lowest frequency of which is not appreciably more than 2.69 MHz. The final IF signal is digitized at a rate that is a multiple of both the symbol frequencies of the QAM and VSB signals, for synchrodyning to baseband, with the 2.69 MHz difference between the carrier frequencies of QAM and VSB signals being taken into account in the digital synchrodyning circuitry. The carrier frequencies of the QAM and VSB final IF signals are regulated to be submultiples of the multiple of both the symbol frequencies of the QAM and VSB signals by applying automatic frequency and phase control signals developed in the digital circuitry to a local oscillator of the tuner.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A radio receiver for receiving a selected one of television signals each including symbol codes descriptive of digital signals, irrespective of whether said selected digital television signal is a quadrature-amplitude-modulation (QAM) signal or is a vestigial-sideband (VSB) signal including a pilot carrier having an amplitude related to signal levels in said symbol codes thereof, said radio receiver comprising: a tuner for selecting said selected television signal, irrespective of whether it is a quadrature-amplitude-modulation (QAM) or a vestigial sideband (VSB) signal, and converting it to a final intermediate-frequency (IF) signal, the carrier of which said final IF signal is a prescribed subharmonic of a multiple of the symbol frequency of said QAM signal if said selected television signal is a QAM signal and is another prescribed subharmonic of a multiple of the symbol frequency of said VSB signal if said selected television signal is a VSB signal, said prescribed subharmonics differing in frequency by substantially 2.69 MHz; QAM synchrodyning circuitry for generating real and imaginary sample streams of QAM symbol code, by synchrodyning said final IF signal to baseband providing it is a QAM signal and otherwise processing said final IF signal as if it were a QAM signal to be synchrodyned to baseband; and VSB synchrodyning circuitry for generating a real sample stream of VSB symbol code, by synchrodyning said final IF signal to baseband providing it is a VSB signal and otherwise processing said final IF signal as if it were a VSB signal to be synchrodyned to baseband.
2. A radio receiver as set forth in claim 1, wherein said prescribed subharmonic of a multiple of the symbol frequency of said QAM signal is substantially 2.69 MHz higher in frequency than said prescribed subharmonic of a multiple of the symbol frequency of said VSB signal.
3. A radio receiver as set forth in claim 1, wherein said prescribed subharmonic of a multiple of the symbol frequency of said QAM signal is substantially 2.69 MHz lower in frequency than said prescribed subharmonic of a multiple of the symbol frequency of said VSB signal.
4. A radio receiver as set forth in claim 1, wherein the real and imaginary sample streams of QAM symbol code supplied by said QAM synchrodyning circuitry are digitized at a sample rate which is harmonically related to said multiple of the symbol frequency of said QAM signal, and wherein the real sample stream of VSB symbol code supplied from said VSB synchrodyning circuitry is digitized at a sample rate which is harmonically related to said multiple of the symbol frequency of said VSB signal.
5. A radio receiver as set forth in claim 4, wherein said multiple of the symbol frequency of said QAM signal and said multiple of the symbol frequency of said VSB signal are the same frequency.
6. A radio receiver as set forth in claim 5, wherein said prescribed subharmonic of a multiple of the symbol frequency of said QAM signal is substantially 2.69 MHz higher in frequency than said prescribed subharmonic of a multiple of the symbol frequency of said VSB signal.
7. A radio receiver as set forth in claim 6, wherein said multiple of the symbol frequency of said QAM signal and said multiple of the symbol frequency of said VSB signal is 129.15 MHz; wherein said prescribed subharmonic of a multiple of the symbol frequency of said QAM signal is the twenty-third subharmonic of 129.15 MHz; and wherein said prescribed subharmonic of a multiple of the symbol frequency of said VSB signal is the forty-seventh subharmonic of 129.15 MHz.
8. A radio receiver as set forth in claim 5, wherein said prescribed subharmonic of a multiple of the symbol frequency of said QAM signal is substantially 2.69 MHz lower in frequency than said prescribed subharmonic of a multiple of the symbol frequency of said VSB signal.
9. A radio receiver as set forth in claim 8, wherein said multiple of the symbol frequency of said QAM signal and said multiple of the symbol frequency of said VSB signal is 129.15 MHz; wherein said prescribed subharmonic of a multiple of the symbol frequency of said QAM signal is the twenty-third subharmonic of 129.15 MHz; and wherein said prescribed subharmonic of a multiple of the symbol frequency of said VSB signal is the fifteenth subharmonic of 129.15 MHz.
10. A radio receiver as set forth in claim 5, wherein the sampling rate at which the real and imaginary sample streams of QAM symbol code supplied by said QAM synchrodyning circuitry are digitized is equal to said same frequency of said multiple of the symbol frequency of said QAM signal and said multiple of the symbol frequency of said VSB signal, and wherein the sampling rate at which the real sample stream of VSB symbol code supplied by said VSB synchrodyning circuitry is digitized is equal to said same frequency of said multiple of the symbol frequency of said QAM signal and said multiple of the symbol frequency of said VSB signal.
11. A radio receiver for receiving a selected one of television signals each including symbol codes descriptive of digital signals, irrespective of whether said selected digital television signal is a quadrature-amplitude-modulation (QAM) signal or is a vestigial-sideband (VSB) signal including a pilot carrier having an amplitude related to signal levels in said symbol codes thereof, said radio receiver comprising: a tuner for selecting said selected television signal, irrespective of whether it is a quadrature-amplitude-modulation (QAM) or a vestigial sideband (VSB) signal, and converting it to a final intermediate-frequency (IF) signal, the carrier of which said final IF signal is a prescribed subharmonic of a multiple of the symbol frequency of said QAM signal if said selected television signal is a QAM signal and is another prescribed subharmonic of a multiple of the symbol frequency of said VSB signal if said selected television signal is a VSB signal, said prescribed subharmonics differing in frequency by substantially 2.69 MHz; an analog-to-digital converter for digitizing said final IF signal to generate a digitized final IF signal; QAM synchrodyning circuitry for generating real and imaginary sample streams of QAM symbol code, by synchrodyning said digitized final IF signal to baseband providing it is a QAM signal and otherwise processing said digitized final IF signal as if it were a QAM signal to be synchrodyned to baseband; and VSB synchrodyning circuitry for generating a real sample stream of VSB symbol code, by synchrodyning said digitized final IF signal to baseband providing it is a VSB signal and otherwise processing said digitized final IF signal as if it were a VSB signal to be synchrodyned to baseband.
12. A radio receiver as set forth in claim 11, wherein said prescribed subharmonic of a multiple of the symbol frequency of said QAM signal is substantially 2.69 MHz higher in frequency than said prescribed subharmonic of a multiple of the symbol frequency of said VSB signal.
13. A radio receiver as set forth in claim 11, wherein said prescribed subharmonic of a multiple of the symbol frequency of said QAM signal is substantially 2.69 MHz lower in frequency than said prescribed subharmonic of a multiple of the symbol frequency of said VSB signal.
14. A radio receiver as set forth in claim 11, wherein the rate at which said analog-to-digital converter digitizes said final IF signal is harmonically related to both said multiple of the symbol frequency of said QAM signal and said multiple of the symbol frequency of said VSB signal.
15. A radio receiver as set forth in claim 14, wherein said multiple of the symbol frequency of said QAM signal and said multiple of the symbol frequency of said VSB signal are the same frequency.
16. A radio receiver as set forth in claim 15, wherein the rate at which said analog-to-digital converter digitizes said final IF signal is equal to said same frequency of said multiple of the symbol frequency of said QAM signal and said multiple of the symbol frequency of said VSB signal.
17. A radio receiver for receiving a selected one of television signals each including symbol codes descriptive of digital signals, irrespective of whether said selected television signal is a quadrature-amplitude-modulation (QAM) signal or is a vestigial-sideband (VSB) signal including a pilot carrier having an amplitude related to signal levels in said symbol codes thereof, said radio receiver comprising: a tuner for selecting said selected television signal, irrespective of whether it is a quadrature-amplitude-modulation (QAM) or a vestigial sideband (VSB) signal, and converting it to a final intermediate-frequency (IF) signal, the carrier of which said final intermediate-frequency (IF) signal is a first prescribed subharmonic of a multiple at least two of 10.76 MHz if said selected television signal is a QAM signal and is a second prescribed subharmonic of said multiple of 10.76 MHz if said selected television signal is a VSB signal, said first and second prescribed subharmonics of said multiple of 21.52 MHz differing in frequency by substantially 2.69 MHz; an analog-to-digital converter for digitizing said final IF signal at a rate harmonically related to 10.76 MHz; digital QAM synchrodyning circuitry for generating real and imaginary sample streams of QAM symbol code, by synchrodyning said digitized final IF signal to baseband providing it is a QAM signal and otherwise processing said digitized final IF signal as if it were a QAM signal to be synchrodyned to baseband; and digital VSB synchrodyning circuitry for generating a real sample stream of VSB symbol code, by synchrodyning said digitized final IF signal to baseband providing it is a VSB signal and otherwise processing said digitized final IF signal as if it were a VSB signal to be synchrodyned to baseband.
18. A radio receiver as set forth in claim 17, wherein said second prescribed subharmonic is substantially 2.69 MHz lower in frequency than said first prescribed subharmonic.
19. A radio receiver as set forth in claim 18, wherein said multiple of 10.76 MHz is 129.15 MHz.
20. A radio receiver as set forth in claim 19, wherein said first prescribed subharmonic is the twenty-third subharmonic of 129.15 MHz and said second prescribed subharmonic is the forty-seventh subharmonic of 129.15 MHz.
21. A radio receiver as set forth in claim 17, wherein said second prescribed subharmonic is substantially 2.69 MHz higher in frequency than said first prescribed subharmonic.
22. A radio receiver as set forth in claim 21, wherein said multiple of 10.76 MHz is 129.15 MHz.
23. A radio receiver as set forth in claim 22, wherein said first prescribed subharmonic is the twenty-third subharmonic of 129.15 MHz and said second prescribed subharmonic is the fifteenth subharmonic of 129.15 MHz.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
April 28, 1998
December 25, 2001
Browse 5M+ US patents with plain-English claim translations and AI-generated analysis.